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Pulse Width Modulation and Inverter
Published in Richard E. Neapolitan, Kwang Hee Nam, AC Motor Control and Electrical Vehicle Applications, 2018
Richard E. Neapolitan, Kwang Hee Nam
The common mode voltage does not incur any current if inverter and motor are floated. However, the motor and the inverter housings should be grounded to provide a common voltage reference for various sensors and communication. Furthermore, frame grounding is necessary for human safety. The frame grounding makes a closed loop with the capacitive couplings. In the case of inverter, the capacitive link is found between IGBT wafer and heat sinking plate. Meanwhile, coil, slot liner, air gap, rotor core, shaft, lubricant film, bearing ball, bearing rail, motor frame etc. form a conductive path inside a motor. Fig. 14.25 shows the loop of common mode current which conducts a big loop consisting of inverter, power cable, motor, and ground system.
State of the art on sustainable manufacturing using mono/hybrid nano-cutting fluids with minimum quantity lubrication
Published in Materials and Manufacturing Processes, 2022
Vaibhav Singh, Anuj Kumar Sharma, Ranjeet Kumar Sahu, Jitendra Kumar Katiyar
In Fig. 1(a) the rolling effect is the result of the physical structure of the nanoparticles in which it acts as a spherical bearing ball between the workpiece and cutting tool that reduces direct metal to metal contact and eventually enhances the life of the cutting tool. Second, the nanoparticles have the propensity to interact with tool-workpiece surface and form a protective layer (Fig. 1b). Mending effect (Fig. 1c) is produced as a result of tribofilm generation due to the agglomeration of nanoparticles in the voids of machining surface that form due to the mass loss. While the polishing effect (Fig. 1d) generates excellent surface finish as a result of controlled abrasion of the work surface by nanoparticles. With the addition of nanoparticles at the cutting zone, the researchers have opined that because of the ultrafine size, the nanoparticles exhibit large surface area-to-volume ratio and thus, provide excellent lubrication over the machining surface. Nika et al.[11] reported that the grooves have filled by copper nanoparticles and disfigurements on the friction surface observed via electron-dispersive spectroscopy and atomic force microscopy. Jang et al.[12] observed the agglomeration of nanoparticles on the surface that reduced the abrasion from the surface and formed a protective layer of lubrication film. Chou et al.[13] reported that the dragged nanoparticles at the contact zone interact with the surface and as a result, the tribological features of cutting fluid was improved. Further, the addition of nanoparticles in the cutting fluid enhanced the thermal conductivity of the fluid and due to which the heat generated at the cutting zone was rapidly dissipated. Moreover, the temperature at the cutting zone can be reduced and thus, the surface quality and tool life were enhanced.
Tribological evaluation of PEG-based nanolubricants modified with graphene and copper oxide
Published in Journal of Dispersion Science and Technology, 2023
Mauricio Perez, Robison Buitrago-Sierra, Karen Cacua, Juan Santa
Two protection mechanism were observed in the SEM: bearing/ball effect (CuO) and deposition of G at valleys and peaks of the surface roughness. Mending effect are observed in the SEM images when the graphene fill the wear surfaces and provide smooth tribopair.